Answer:
Phosphorylation within the nuclear export signal interferes with the function of the  signal.
Explanation:
In biochemistry, phosphorylation is the addition of a phosphate group (PO4) to a protein or other molecule. Phosphorylation is a major player in protein regulation mechanisms, preventing protein-catalyzed reaction product from accumulating in the body causing problems.
However, in some cases phosphorylation may cause nuclear accumulation of a protein in the nucleus of the cell. An example of this is the protein shown in the question above. In this case, phosphorylation in the nuclear export signal interferes with the signal function, resulting in protein accumulation in the nucleus.
 
        
             
        
        
        
Earth had essentially no atmosphere when it originated 4.6 billion years ago from a heated mixture of gases and minerals. The ground had melted on it. 
An atmosphere developed when Earth cooled, primarily from gases released by volcanoes. It contained methane, hydrogen sulfide, and ten to 200 times as much carbon dioxide as the atmosphere we are surrounded by today. The Earth's surface began to cool and solidify after roughly 500 million years, allowing water to accumulate there. Although life on Earth continued to develop and diversify, such periods of expansion and development were halted by mass extinctions, in which many of the planet's major life forms were either entirely or partially wiped out and many others were freshly established. Such catastrophic extinction episodes are attributed to asteroids impacts, climate change, volcanic eruptions, etc. Dinosaurs were also wiped out in one such event. The largest problem the Earth is currently experiencing is climate change brought on by human activity. Although human activities may exterminate some species from the world, the planet will undoubtedly recover and return to its natural balance as it has for millions of years. However, the sun will ultimately wipe out Earth, as predicted by scientists. The Sun will lose its structural integrity and enlarge in volume as it ages and eventually runs out of the fuel that keeps it going—hydrogen—which will cause it to burn everything in its path, including life on Earth. In the end, the Sun would perish, leaving the Solar System permanently in the dark.
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